Epilogue

Author(s):  
Timothy Clifton

Our understanding of gravity has developed rapidly over the past century. This began with Einstein’s revolutionary new theory and continued with sustained developments in both our understanding of the mathematics and observations that can be used to probe it. This VSI outlines how new gravitational effects have been predicted and observed in the Solar System; in exotic astrophysical systems; and in the Universe as a whole. The ‘Epilogue’ explains that although this VSI attempts to give some idea of the elegance of the concepts involved, and the details of the wondrous physics that results, it is inevitably left incomplete. The final words on gravity have yet to be written.

Author(s):  
Karel Schrijver

How many planetary systems formed before our’s did, and how many will form after? How old is the average exoplanet in the Galaxy? When did the earliest planets start forming? How different are the ages of terrestrial and giant planets? And, ultimately, what will the fate be of our Solar System, of the Milky Way Galaxy, and of the Universe around us? We cannot know the fate of individual exoplanets with great certainty, but based on population statistics this chapter sketches the past, present, and future of exoworlds and of our Earth in general terms.


2009 ◽  
Vol 5 (S260) ◽  
pp. 33-38
Author(s):  
Lawrence M. Krauss

AbstractCosmological discoveries over the past century have completely changed our picture of our place in the universe. New observations have a realistic chance of probing nature on heretofore unimaginable scales, and as a result are changing the nature of fundamental science. Perhaps no other domain of science has an equal capacity to completely change our perspective of the world in which we live.


1985 ◽  
Vol 112 ◽  
pp. 151-156
Author(s):  
Clifford N. Matthews

Current research in cosmochemistry shows that crude organic solids of high molecular weight are readily formed in planetary, interplanetary and interstellar environments. What are the components of these intractable materials and how are they connected, if at all, with the beginnings of life? It is proposed here that underlying much of this ubiquitous chemistry is a low energy route leading directly to the synthesis of heteropolypeptides from hydrogen cyanide and water. Evidence from laboratory and extraterrestrial investigations suggests that this hydrogen cyanide polymerization is a truly universal process that accounts not only for the past synthesis of protein ancestors on Earth but also for reactions proceeding elsewhere today within our solar system, on planetary bodies around other stars and in the dusty molecular clouds of spiral galaxies. The existence of this preferred pathway adds greatly to the probability of life being widespread in the universe.


Author(s):  
Matthew S. Moses ◽  
Gregory S. Chirikjian

The concept of an artificial corporeal machine that can reproduce has attracted the attention of researchers from various fields over the past century. Some have approached the topic with a desire to understand biological life and develop artificial versions; others have examined it as a potentially practical way to use material resources from the moon and Mars to bootstrap the exploration and colonization of the solar system. This review considers both bodies of literature, with an emphasis on the underlying principles required to make self-replicating robotic systems from raw materials a reality. We then illustrate these principles with machines from our laboratory and others and discuss how advances in new manufacturing processes such as 3-D printing can have a synergistic effect in advancing the development of such systems.


2020 ◽  
Vol 3 (4) ◽  
pp. 203-218
Author(s):  
A.E. Razumov ◽  

The last century is filled with victories and failures, passions, and interests. World wars and revolutions, the change of political regimes, ideologies, and ideological orientations — all this provoked a formation of social and political chaos, which sometimes had to be overcome in a totalitarian way through sole commanding and by one-party dictatorship. At the same time, one can observe the successes of cognition, culture, scientific and technological development, which, however, can hardly be called “progress”. Because the mass destruction weapons of certain “partners” in globalism have also been increased. Ready for self-destruction, “man in time” did not become yet the master of his destiny in the last century, but in many ways remained a mystery to himself. Despite the fact that over the past century man has learned a lot about his own psychology, consciousness and subconscious, he still needs further self-knowledge no less than in those times when the Oracle of Delphi called for it. Today, as ancient times, one needs to know better what motivates his sometimes rational, and sometimes, mildly speaking, very strange behavior. Who is man in time? To understand this, one must go beyond the limits of itself being to other times and spaces. Even to times and spaces of a cosmic scale, to the spaces and to the depths of our Universe, where a man was born and will disappear, perhaps preserved in its cosmic memory. The memory of the Universe is symbolized by world constants that arose as a result of the Big Bang and the birth of the Universe from a singularity point. Memory of man inherits this property of the Cosmos. The memory is a system-forming factor that creates man and its world. This is what rigorous science can offer to explain the cosmic origin of man and his memory. Artistic imagery can continue the efforts of science. Culture, literature, first of all, can create imageries that will tell about man and his time more than abstract theory. The imageries will tell that man has not yet lost his freedom of creativity. He must remember the past, live in the present, look and go to the future.


1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.


1962 ◽  
Vol 11 (02) ◽  
pp. 137-143
Author(s):  
M. Schwarzschild

It is perhaps one of the most important characteristics of the past decade in astronomy that the evolution of some major classes of astronomical objects has become accessible to detailed research. The theory of the evolution of individual stars has developed into a substantial body of quantitative investigations. The evolution of galaxies, particularly of our own, has clearly become a subject for serious research. Even the history of the solar system, this close-by intriguing puzzle, may soon make the transition from being a subject of speculation to being a subject of detailed study in view of the fast flow of new data obtained with new techniques, including space-craft.


2020 ◽  
Vol 4 (4) ◽  
pp. 365-381
Author(s):  
Ny Anjara Fifi Ravelomanantsoa ◽  
Sarah Guth ◽  
Angelo Andrianiaina ◽  
Santino Andry ◽  
Anecia Gentles ◽  
...  

Seven zoonoses — human infections of animal origin — have emerged from the Coronaviridae family in the past century, including three viruses responsible for significant human mortality (SARS-CoV, MERS-CoV, and SARS-CoV-2) in the past twenty years alone. These three viruses, in addition to two older CoV zoonoses (HCoV-229E and HCoV-NL63) are believed to be originally derived from wild bat reservoir species. We review the molecular biology of the bat-derived Alpha- and Betacoronavirus genera, highlighting features that contribute to their potential for cross-species emergence, including the use of well-conserved mammalian host cell machinery for cell entry and a unique capacity for adaptation to novel host environments after host switching. The adaptive capacity of coronaviruses largely results from their large genomes, which reduce the risk of deleterious mutational errors and facilitate range-expanding recombination events by offering heightened redundancy in essential genetic material. Large CoV genomes are made possible by the unique proofreading capacity encoded for their RNA-dependent polymerase. We find that bat-borne SARS-related coronaviruses in the subgenus Sarbecovirus, the source clade for SARS-CoV and SARS-CoV-2, present a particularly poignant pandemic threat, due to the extraordinary viral genetic diversity represented among several sympatric species of their horseshoe bat hosts. To date, Sarbecovirus surveillance has been almost entirely restricted to China. More vigorous field research efforts tracking the circulation of Sarbecoviruses specifically and Betacoronaviruses more generally is needed across a broader global range if we are to avoid future repeats of the COVID-19 pandemic.


VASA ◽  
2018 ◽  
Vol 47 (3) ◽  
pp. 165-176 ◽  
Author(s):  
Katrin Gebauer ◽  
Holger Reinecke

Abstract. Low-density lipoprotein cholesterol (LDL-C) has been proven to be a causal factor of atherosclerosis and, along with other triggers like inflammation, the most frequent reason for peripheral arterial disease. Moreover, a linear correlation between LDL-C concentration and cardiovascular outcome in high-risk patients could be established during the past century. After the development of statins, numerous randomized trials have shown the superiority for LDL-C reduction and hence the decrease in cardiovascular outcomes including mortality. Over the past decades it became evident that more intense LDL-C lowering, by either the use of highly potent statin supplements or by additional cholesterol absorption inhibitor application, accounted for an even more profound cardiovascular risk reduction. Proprotein convertase subtilisin/kexin type 9 (PCSK9), a serin protease with effect on the LDL receptor cycle leading to its degradation and therefore preventing continuing LDL-C clearance from the blood, is the target of a newly developed monoclonal antibody facilitating astounding LDL-C reduction far below to what has been set as target level by recent ESC/EAS guidelines in management of dyslipidaemias. Large randomized outcome trials including subjects with PAD so far have been able to prove significant and even more intense cardiovascular risk reduction via further LDL-C debasement on top of high-intensity statin medication. Another approach for LDL-C reduction is a silencing interfering RNA muting the translation of PCSK9 intracellularly. Moreover, PCSK9 concentrations are elevated in cells involved in plaque composition, so the potency of intracellular PCSK9 inhibition and therefore prevention or reversal of plaques may provide this mechanism of action on PCSK9 with additional beneficial effects on cells involved in plaque formation. Thus, simultaneous application of statins and PCSK9 inhibitors promise to reduce cardiovascular event burden by both LDL-C reduction and pleiotropic effects of both agents.


1901 ◽  
Vol 51 (1309supp) ◽  
pp. 20976-20977
Author(s):  
W. M. Flinders Petrje
Keyword(s):  

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